New Brunswick's justice minister says he may invoke the Constitution to protect a provincial commission that regulates investments.

Mike Murphy's comments come after Ottawa's decided to go to court to try to set up a single national securities regulator.

"I will use any grounds available to me — legal, procedural or otherwise — to protect the interests of the New Brunswick Securities Commission and its status in New Brunswick and Saint John, and those jobs," he said.

Some corporations say dealing with 13 separate securities regulators in Canada is inefficient. So Ottawa is asking the Supreme Court to rule it's constitutional to set up a single national regulator.

Murphy said the province hasn't decided whether to fight that move but it may, for pragmatic reasons.

He has written to federal Finance Minister Jim Flaherty to say he's not ready to give up on the New Brunswick Securities Commission, which has provided more than $28 million in revenue to the province in five years and employs about 30 people in Saint John.

Provincial commissions have set up reciprocal agreements to eliminate inefficiencies, said commission chairman David Barry.

"If people file or an issuer files in Ontario, it's good for New Brunswick, and if you have New Brunswick companies file in New Brunswick, that's good for the rest of the country," he said.

It's not known when Ottawa's case will go to court, or when New Brunswick will decide whether to intervene.

Meanwhile, the Canadian Securities Transition Office is consulting provinces and territories, securities experts and legal advisers as it develops plans for the structure and management of a new regulator.